A clear link between the hydrocarbon and borohydride chemistries is established by showing that hydrocarbons and borohydrides have a common root regulated by the number of valence electrons in a confined space. Application of the proposed method to archetypal hydrocarbons leads to well-known borohydrides but, more importantly, it allows the design of new and interesting boron-containing molecules that can be a source of inspiration for synthetic chemists.